Sir Michael Palin is backing a national campaign to help safeguard the nation's historic churches for future generations.
The campaign comes at a challenging time for churches, with dozens of closures every year and the economic pressures of dwindling congregations compounded by the pandemic.
As part of the campaign, the National Churches Trust is inviting people to take part in a national debate about how historic churches can survive into the future.
"The UK has over 39,000 church buildings. The restrictions of Covid-19, resulting in reduced funding and fewer worshippers, has clouded the future for many of them," said Sir Michael.
"Yet churches remain a vital and much-loved part of the UK's history and heritage and we can't let them fall into neglect and disuse.
"There is hope. More and more churches are adapting to the modern world and the needs of their communities, providing not just spiritual comforts but a range of valuable services to local people such as foodbanks and youth clubs.
"We must build on this, and encourage people of all sorts and from all backgrounds to find hope and relevance in their local churches."
Claire Walker, CEO of the National Churches Trust said: "Church buildings belong to all of us and that's why we are starting a national debate about their future.
"Whether you are a regular churchgoer, a heritage lover or have been in a church recently to have your Covid vaccination, please do take part and tell us what you think."
Figures from Brierley Research Consultancy show that the number of churches open and used for worship has fallen from 42,000 to 39,800 in the last 10 years.
The National Churches Trust said church closures were "particularly acute" in inner-city areas and that congregations, especially in rural areas, were struggling to keep up with the cost of urgent repairs.
Funding shortages are a "key factor" in church closures, it has warned.
Sir Michael added, "If you care as much as I do about the future of these much loved buildings, do get involved with the National Churches Trust debate about 'The Future of Churches' and help shape their future."
Ms Walker continued, "Right now, many church buildings are in danger. That's because there isn't enough money available to fund urgent repairs and maintenance or to install essential facilities such as toilets and kitchens.
"Over 900 churches are on the Historic England 'Heritage at Risk Register', with many more in a dire state in Scotland, Wales and Northern Ireland.
"Church buildings are a unique national asset. It would be a huge mistake to let them decay when they provide around £55 billion of economic and social value to the UK each year."
She added, "Our vision is that church buildings across the UK are well maintained, open to everyone, sustainable and valued. At the National Churches Trust we will continue to do everything we can to support church buildings as we all stand to lose if we let them disappear."
